JP3498938B2 - Heating roller support device, fixing device, electrophotographic device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating roller supporting device, a fixing device, and an electrophotographic device. 2. Description of the Related Art An electrophotographic apparatus is provided with a fixing device for fixing a transfer image transferred from an image carrier to a transfer sheet. This fixing device has a structure in which a pressure roller is elastically contacted with a rotatable heating roller through which a heater tube is inserted. As described in Japanese Utility Model Laid-Open Publication No. Sho 59-176055, for example, the heating roller of the fixing device of this type connects both ends of a heater tube inserted thereinto to a power supply unit. An open cylindrical shape is often used. The heating roller proposed in this publication is rotatably supported by bearings in which sliding sleeves fitted on the outer periphery of both ends thereof are fixed to opposing side surfaces of a housing. The inward flange integrally formed on the outer end surface of the heat roller is prevented from coming into contact with the end surface of the sliding sleeve and the end surface of the heating roller. In the above-described heating roller support structure, since the thickness of the tube of the heating roller is thin, the inner flange is liable to be damaged unless the finishing precision is improved, and the rotation of the heating roller is difficult. Also becomes unsmooth. In addition, although it is necessary to fit the driving force transmission gears to the heating roller in a state where they are not rotated, as a conventional example including this proposal, in order to connect the heating roller and the driving force transmission gear, the heating roller is connected to the heating roller. A keyway along the axial direction is cut out from its end, a rib-shaped key is formed on the driving force transmission gear, and both keys are aligned while aligning the keying of the driving force transmission gear with the keyway of the heating roller. And the rotation of the driving force transmission gear is transmitted to the heating roller by engagement of the key groove and the key. In this case, the periphery of the end surface of the heating roller becomes discontinuous due to the formation of the key groove at one end opening.
If the movement of the heating roller in the axial direction is suppressed by a pressing member such as an inward flange as described in Japanese Patent No. 176055, there is a problem that the pressing member is severely worn and the rotation performance is extremely deteriorated. SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and has as its object to smoothly support a heating roller with a small number of components. [0012] The roller support device according to the first aspect of the present invention is configured such that both end openings rotatably supported by bearings provided on opposed support plates. A heating roller having a cylindrical shape, a key groove formed with a predetermined length in the axial direction on a peripheral surface of an end portion of the heating roller, and an axially movable and rotatable direction with respect to the key groove. A driving force transmission gear formed by projecting a key inserted and prevented from rotating, a stopper formed integrally with the support plate and abutting on an end surface orthogonal to an axis of the driving force transmission gear, and the key; And a resilient locking piece disposed at a part of the inside of the groove, integrally formed with the heating roller, and engaged with an end surface of the key. Therefore, the heating roller and the driving force transmission gear are connected so as to rotate integrally by fitting the key into the key groove. Further, the axial movement of the driving force transmission gear in the direction in which the driving force transmission gear comes off from the end of the heating roller is fixed by the contact between the driving force transmission gear and the stopper. In this case, the stopper can be brought into contact with the flat end surface of the driving force transmission gear, so that the heating roller and the driving force transmission gear rotate smoothly. Further, the axial movement of the heating roller in the direction in which the heating roller comes off from the driving force transmission gear can be fixed without depending on other members by the engagement between the end face of the key and the elastic locking piece. . In this case, the elastic locking piece can be processed at the same time when the key groove is processed by a press or the like. An embodiment of an electrophotographic apparatus according to the present invention will be described with reference to FIG. In the figure, reference numeral 1 denotes an apparatus main body. An image reading device 2 for reading an image of a document is mounted on an upper portion of the apparatus main body 1, and a process cartridge 3 is provided inside. Below the process cartridge 3, a paper transport path 4 for guiding transfer paper is formed. The image reading apparatus 2 has a reading section 5 for reading a document image, and a document tray 6 on which a document to be supplied to the reading section 5 is placed.
Is supported so as to be able to pivot upward from a horizontal position to a position indicated by a virtual line B with. The document tray 6 is configured to be stabilized between a horizontal position and a position indicated by a virtual line B by a stopper (not shown). In the process cartridge 3, an image carrier 9 is rotatably provided on a unit body 8 formed in a case shape, and a charging brush roller 10 and a developing unit 11 are provided.
And the transfer section 12 are arranged and attached around the image carrier 9. The developing unit 11 includes a developer container 13 formed integrally with the unit main body 8, a rotatable stirrer 14 for stirring the developer housed inside the developer container 13, and an image carrier 9. A developing roller 15 that comes into contact with the developing roller 15; a supply roller 16 that supplies developer to the developing roller 15;
And 7. Further, a latent image forming unit 18 that forms an electrostatic latent image by scanning a charged portion of the image carrier 9 with laser light modulated based on an image signal is provided above the process cartridge 3. . On one side of the apparatus main body 1, a tray 19 for supporting the original read by the image reading apparatus 2 and supporting the transfer paper S in an obliquely mounted state is provided. Below the sheet feeding roller 20, a pressing plate 21 urged in one direction to press the transfer sheet S on the tray 19 against the sheet feeding roller 20,
A separation pad 22 and a separation roller 23 are provided, each of which elastically contacts the paper feed roller 20 to prevent double transfer of the transfer paper S. The paper feed roller 20, the separation pad 22, and the separation roller 23 are arranged on the entrance side of the paper transport path 4. A bottom path 24 located downstream of the paper feed roller 20 communicates with the paper transport path 4. Further, a fixing unit 25 for fixing an image transferred onto the transfer sheet S is disposed downstream of the sheet transport path 4. Further, a fixing device 2 is provided in the apparatus main body 1.
A paper stacker 26 is formed between the upper part 5 and the document tray 6. This paper stacker 26
Has a receiving plate 27 that is positioned on the extension surface of the document tray 6 and supports the transfer sheet S when the document tray 6 is rotated on the virtual line B. Further, in the vicinity of the side surface of the apparatus main body 1 opposite to the tray 19, a discharge port 28 for discharging the transfer paper S discharged from the fixing device 25 in the horizontal direction.
And a reverse discharge path 29 that reverses the transfer sheet S discharged from the fixing device 25 and guides the transfer sheet S to the sheet stacker 26. A pair of paper discharge rollers 30 is disposed on the upper and lower sides of the reverse paper discharge path 29, and the transfer paper S is discharged at a branch point between the reverse paper discharge path 29 and the paper discharge port 28. A switching claw 31 for switching the direction is provided rotatably. Although the structure of the fixing device 25 will be described later, a heating roller 33 rotatably supported on both sides of the housing 32, and a pressure roller 34 supported so as to elastically contact the heating roller 33 are provided. have. Next, an image reading operation and a printing operation will be described. When reading an image of a document, the document is supplied to the reading unit 5 while the document tray 6 is kept horizontal as shown by a solid line in FIG. The image of the supplied document is read by the reading unit 5, and the document is supported on the tray 19 in an upright state. The image read in this way is transmitted to the outside (use mode as facsimile transmission mode)
Alternatively, the transfer sheet S can be fed from the tray 19 and the read image can be printed on the transfer sheet S (use form as a copying machine). Alternatively, an image transmitted from the outside can be printed on the transfer sheet S (use mode as a facsimile reception mode). In the case of printing, in FIG. 15, the surface of the image carrier 9 is charged by the charging brush roller 10 in the process of rotating the image carrier 9 clockwise, and a latent image is formed based on a read image of a document or an image received from outside. The forming unit 18 forms an electrostatic latent image on a charged portion of the image carrier 9. This electrostatic latent image is developed by the developing unit 11. This developed image is transferred from the transfer sheet S fed from the tray 19 by the feed roller 20.
Is transferred to The transfer sheet S on which the image has been transferred is fixed when passing through the fixing device 25, and is discharged to the sheet discharge port 28 or the sheet stacker 26 depending on the direction of the switching claw 31. Next, the structure of the heating roller supporting device used in the electrophotographic apparatus will be described. First, it will be described with reference an exemplary structure of a pressurized heat roller supporting apparatus 35 in FIGS. As shown in FIG.
The housing 32 has support plates 36 and 37 opposed to each other, and bearings 38 and 37 provided on these support plates 36 and 37 are provided.
A heating roller 33 is rotatably supported by 39. One of the bearings 38 has its axial and circumferential movements fixed by fitting a flange 40 formed on the outer periphery thereof into a groove 41 formed in the support plate 36. The other bearing 39
Is fixed to the support plate 37 by screws 42, and the bearing 39
Has an inner flange 43 abutting on the end face of the heating roller 33.
Is formed. The heating roller 33 is formed by using a cylindrical raw tube having both ends opened in order to connect both ends of the heater tube 44 inserted thereinto to the power supply unit, and a motor (not shown) is provided on the outer periphery of the end. A driving force transmission gear 45 for transmitting the driving force is fitted. As shown in FIG. 2, one end of the heating roller 33 has a key groove 46 having a predetermined length in the axial direction from the end surface thereof.
A key 47 that is movable in the axial direction with respect to the key groove 46 and is prevented from rotating in the rotational direction is integrally formed on the inner peripheral surface of the driving force transmission gear 45. Further, as shown in FIG. 1, one of the support plates 36 is provided with a stopper 4 abutting on an end surface 48 orthogonal to the axis of the driving force transmission gear 45.
9 are integrally formed. In such a configuration, the heating roller 33
The driving force transmission gear 45 and the driving force transmission gear 45 are connected so as to rotate integrally by fitting the key 47 into the key groove 46. Further, the axial movement of the driving force transmission gear 45 in the direction in which the driving force transmission gear 45 is pulled out from the end (left end in FIG. 1) of the heating roller 33 is fixed by the contact between the driving force transmission gear 45 and the stopper 49. Is done. In this case, one end of the heating roller 33 on the driving force transmission gear 45 side is discontinuous because one end of the key groove 46 is opened, but the stopper 49 is applied to the flat end surface 48 of the driving force transmission gear 45. Since the heating roller 33 and the driving force transmission gear 45 can rotate smoothly, they can be brought into contact with each other. In this case, when the left end of the heating roller 33 coincides with or protrudes beyond the end face of the driving force transmission gear 45, the stopper 49 is rubbed against the notch of the key groove 46 of the heating roller 33, and is worn or rotated. May be unsmooth. Therefore, the dimensional relationship between the heating roller 33 and the driving force transmission gear 45 is determined by comparing the end surface 48 of the driving force transmission gear 45 with the heating roller 33.
In this case, one end of the heating roller 33 where the key groove 46 is formed is prevented from interfering with the stopper 49. This is an effect corresponding to the second aspect of the present invention. In FIG. 1, the rightward movement of the gear 45 is caused by the contact of the key 47 with the rear end of the key groove 46 or the inner side of the driving plate 45 with the support plate 36 or the bearing 38. Can be limited by the contact with the end face of the lens. Also,
The movement of the heating roller 33 to the right in the axial direction with respect to the gear 45 whose movement in the left-right axial direction is prevented by the support plate 36 and the stopper 49 is caused by the inner flange 43 of the bearing 39 in this example.
Is blocked by At the time of assembly, the right support plate 37
Before the bearing 39 is attached to the keyway 46, the driving force transmission gear 45 is positioned between the left support plate 36 and the stopper 49, and the heating roller 33 is inserted from the right support plate 37 side, and the key groove 46 is inserted. After fitting the heating roller 33 and the driving force transmission gear 45 while adjusting the positions of the heating roller 33 and the key 47 in the rotation direction, the bearing 39 is attached to the right support plate 37. Next, the structure of the pressurized heat roller support device 50
Another example will be described with reference to FIGS. The following theory
In the following description, the same parts as those described with reference to FIGS. As shown in FIG. 4, at the left end of the heating roller 33, a notch 51 is formed along the circumferential direction on both side edges in the middle of the key groove 46, and a tongue piece 52 adjacent to the notch 51. Is formed. The notch 51 is used for assembling the tongue piece 5 during assembly.
2 is formed to make it easier to bend outward. Also,
The driving force transmission gear 45 is formed with a locking recess 53 located near the edge of the key 47 and an annular rib 54 having a semicircular cross-sectional shape and protruding from the end face. In such a configuration, when the heating roller 33 and the driving force transmission gear 45 are fitted together while the key groove 46 and the key 47 are being aligned, the tongue piece 52 is locked at the end of the key 47. Since the tongue piece 52 is bent outward in the radial direction to form the bent piece 55 because the tongue piece 52 is opposed to the recessed part 53, these bent pieces 55 engage with the locking recessed part 53. In this state, as described above, the axial movement of the driving force transmission gear 45 in the direction in which the driving force transmission gear 45 comes off from the end of the heating roller 33 is caused by the movement of the driving force transmission gear 45 and the stopper 49. Fixed by contact with Further, the rightward movement of the heating roller 33 in the direction in which the heating roller 33 comes off from the driving force transmission gear 45 can be fixed by the engagement of the bent bent piece 55 and the locking recess 53. It becomes. Therefore, the rightward movement of the heating roller 33 can be prevented without depending on other members such as the inner flange 43 of the bearing 39 shown in FIG.
Thereby, the structure of the bearing 39 is simplified, and in some cases, the bearing portion can be formed integrally with the support plate 37. Further, the stopper 4 of the driving force transmission gear 45
Since the annular rib 54 having a semicircular cross-sectional shape is formed at the portion that comes into contact with 9, the friction at the contact surface can be reduced, and the rotation performance can be further improved. Next, an example of the underlying structure of the pressurized heat roller support device 56 of the present invention will be described with reference to FIGS. 6-8. At the end of the heating roller 33, an elastic locking piece 57 which can be deformed in the radial direction by its own elasticity, and a slot 58 surrounding three sides of the elastic locking piece 57 are formed. The slot 58 is formed to make the elastic locking piece 57 easily deformable. The elastic piece 57 is arranged on the side opposite to the position where the key groove 46 is formed. Further, a concave portion 59a and a concave portion 5
A protruding locking portion 59 (see FIG. 6) which is located at the back of 9a and engages with the elastic locking piece 57 is formed. In such a configuration, the heating roller 33
The axial movement of the driving force transmission gear 45 in the leftward direction in which the driving force transmission gear 45 is pulled out from the end portion is fixed by the contact between the driving force transmission gear 45 and the stopper 49. The rightward movement of the heating roller 33 in the axial direction in which the heating roller 33 is pulled out of the driving force transmission gear 45 is caused by the elastic locking piece 57 being locked when the heating roller 33 and the driving force transmission gear 45 are fitted. It can be fixed to engage with the portion 59. Also in this case, the rightward movement of the heating roller 33 can be prevented without depending on other members such as the inner flange 43 of the bearing 39 shown in FIG. Next, another example of the structure of the heating roller supporting device 60 which forms the basis of the present invention will be described with reference to FIGS. 9 and 10. At the end of the heating roller 33, a projection 61 projecting in the radial direction is integrally formed. The protrusion 61 is arranged on the opposite side of the position where the key groove 46 is formed. The driving force transmission gear 45 is integrally formed with an elastically deformable engaging portion 62 which is engaged with the projection 61 and relatively restricts axial movement with respect to the heating roller 33. The driving force transmission gear 45 is formed of an elastic synthetic resin. Therefore, the movement of the driving force transmission gear 45 to the left in the axial direction in the direction in which the driving force transmission gear 45 comes off from the end of the heating roller 33 is caused by the movement of the driving force transmission gear 45 and the stopper 49.
Fixed by contact with Further, the driving force transmission gear 45
The movement of the heating roller 33 to the right side in the axial direction of the direction in which the heating roller 33 comes off from the shaft is such that the locking portion 62 elastically engages with the projection 61 when the heating roller 33 and the driving force transmission gear 45 are fitted. Therefore, it can be fixed. Also in this case, the rightward movement of the heating roller 33 can be prevented without depending on other members such as the inner flange 43 of the bearing 39 shown in FIG. Here, the elastic locking piece 57 shown in FIG.
Since a slot 58 must be formed around the periphery for elastic movement, the die facing the punch facing the slot 58 is necessarily larger than the punch. It is difficult to insert the small diameter heating roller 33 into the base tube. However, in the present embodiment, the projection 61 projecting in the radial direction to be engaged with the locking portion 62 of the driving force transmission gear 45 is formed by pressing.
Does not need to be sheared, so a small press die can be used. This is advantageous in using the small-diameter heating roller 33 as compared with the case where the elastic locking piece 57 is processed as shown in FIG. [0043] Furthermore, a description will be given of a structure of the heating roller supporting apparatus 63 in the embodiment of the first aspect of the present invention in FIGS. 11 to 14. A key groove 64 into which the key 47 of the driving force transmission gear 45 is inserted, and an elastic locking piece 65 continuous from one end of the key groove 64 are formed on the outer periphery of the left end of the heating roller. Therefore, when the left end of the heating roller 33 and the driving force transmission gear 45 are fitted together, the elastic locking piece 65 is pressed by the key 47 and thus deforms inward. When it moves to the back of the key 47, it returns by its own elasticity and engages with the end of the key 47. In this state, as shown in FIG.
The axial movement of the driving force transmission gear 45 in the direction in which
The driving force transmission gear 45 and the stopper 49 are fixed by abutment. Also, the driving force transmission gear 45 transfers the heat roller 33
The movement of the heating roller 33 to the right in the axial direction in the direction in which the key 47 comes off can be fixed by the engagement between the end face of the key 47 and the elastic locking piece 65. Also in this case, the rightward movement of the heating roller 33 can be prevented without depending on other members such as the inner flange 43 of the bearing 39 shown in FIG. Further, the elastic locking piece 65 can be processed simultaneously when the key groove 64 is processed by a press or the like. [0045] [0046] [0047] [0048] [0049] [0050] wherein the roller supporting device according to item 1, wherein the heating roller cylindrical in bearings supported across an opening provided on the support plate opposing And a driving force transmitting gear for transmitting a driving force to the heating roller, and a key groove having a predetermined length in an axial direction is provided on a peripheral surface of an end portion of the heating roller, and the key groove is disposed inside a part of the key groove. A key that is movable in the axial direction with respect to the key groove, is prevented from rotating in the rotational direction, is inserted into the key groove, and has an end face elastically engaged with the elastic locking piece. Since the driving force transmission gear is formed integrally, the heating roller and the driving force transmission gear can be connected so as to rotate integrally by fitting a key into the key groove. Further, the axial movement of the driving force transmission gear in the direction in which the driving force transmission gear is removed from the end of the heating roller can be fixed by the contact between the driving force transmission gear and the stopper.
In this case, the stopper can be brought into contact with the flat end surface of the driving force transmission gear, so that the heating roller and the driving force transmission gear rotate smoothly. Further, the axial movement of the heating roller in the direction in which the heating roller comes off from the driving force transmission gear can be fixed without depending on other members by the engagement between the end face of the key and the elastic locking piece. In this case, the elastic locking piece can be simultaneously processed when the keyway is processed by a press or the like. [0051]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional side view showing an example of a structure of a heating roller supporting device 35. FIG. 2 is a perspective view illustrating a relationship between a heating roller and a driving force transmission gear. FIG. 3 is a vertical sectional side view showing another example of the heating roller supporting device. FIG. 4 is a perspective view showing a relationship between a heating roller and a driving force transmission gear. FIG. 5 is an end view of the connection structure between the heating roller and the driving force transmission gear as viewed from one end in the axial direction. FIG. 6 is a vertical sectional side view showing a part of a heating roller supporting device as an example of a configuration serving as a basis of the present invention . FIG. 7 is a perspective view illustrating a relationship between a heating roller and a driving force transmission gear. FIG. 8 is a side view showing a part of the heating roller. FIG. 9 is a vertical sectional side view showing a part of a heating roller supporting device as another example of a configuration serving as a basis of the present invention . FIG. 10 is a partially longitudinal side view showing, in an enlarged manner, a connection structure between a heating roller and a driving force transmission gear. 11 is a vertical sectional side view showing a part of the heating roller supporting apparatus according to an embodiment of the first aspect of the present invention. FIG. 12 is a perspective view showing a relationship between a heating roller and a driving force transmission gear. FIG. 13 is a side view showing a part of the heating roller. FIG. 14 is a longitudinal sectional side view showing a connection structure between a heating roller and a driving force transmission gear. FIG. 15 is a vertical sectional front view showing the internal structure of the electrophotographic apparatus. [Description of Signs] 9 Image carrier 11 Developing unit 12 Transfer unit 18 Latent image forming unit 25 Fixing device 33 Heating roller 34 Pressurizing roller 35 Heating roller supporting devices 36, 37 Support plates 38, 39 Bearing 45 Driving force transmission gear 46 Key groove 47 Key 48 End face 49 of driving force transmission gear Stopper 50 Heating roller support device 53 Locking recess 55 Bending piece 56 Heating roller support device 57 Elastic locking piece 59 Locking portion 60 Heating roller support device 61 Projection 62 Locking Part 63 heating roller support device 65 keyway

Claims (1)

(1) Claims 1. A cylindrical heating roller having both ends opened rotatably supported by bearings provided on opposing support plates, and a peripheral surface of an end portion of the heating roller. A keying groove formed with a predetermined length in the axial direction, and a driving force transmitting gear formed with a key protrudingly formed so as to be movable in the axial direction with respect to the key groove and to be prevented from rotating in the rotating direction. A stopper integrally formed on the support plate and abutting on an end surface orthogonal to the axis of the driving force transmission gear; and a stopper arranged on a part of the inside of the key groove and integrally formed on the heating roller. And a resilient engagement piece engaged with an end face of the key.